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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        let arr = new Array(20, 30, 40, 50, 6, 100)
        function getGrade(newArr = new Array()) {
            let num = 0
            for (let i = 0; i < newArr.length; i++) {
                num += newArr[i]
            }
            console.log(num);
        }
        getGrade(arr)
    </script>
</body>

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